While a lot has been written on the subject of epicondylitis, there existe little sound emperical evidence on the most appropriate treatment. However what can be said from clinical experience is that the use of modalities has very little effect. I would suggest that a regime of stretching/strengthening exercises on a graduated scale over a period of six weeks combined with Soft tissue, Manual and/or Manipulative therapy is perhaps the best direction. I refer you to the following article that may shed some light on the subject.

Vicenzino, B., Paungmali, A., Buratowski, S. and Wright, A. 2001, Specific manipulative therapy treatment for chronic lateral epicondylalgia produces uniquely characteristic hypoalgesia. Manual Therapy. 6(4), pp. 205-212.